sam314159

I've been getting an occasional cylinder 3 misfire code so I pulled the engine cover off last night and swapped ignition coils 2 and 3 to see if the code follows the coil. It hasn't thrown another code yet but I can still sense the hesitation.

My car is due for spark plugs anyway (56k) so I have 6 new ones on the way.

My question is about what I saw in spark plug 3 well. It looked like there was a little corrosion. Well #2 was pristine. Is this indicative of another possible issue?

Thanks.

Car:
- 2008 535i Automatic
- Updated to latest BMW software
- 56k miles

KyleB

First off, OMG that's a lot of pictures on your phone.

No, I wouldn't worry about it. It looks to me like the residue is on the outer boot. As long as the coil is making good contact with the plug, that's all that counts. Did someone power-wash the engine at some point? I'm wondering if some water got trapped down there in the well.

sam314159

Haha yeah I guess I got carried away with the pictures. I am so ready for a 64GB phone.

I never did it and I kinda doubt the dude before me did. He babied this car and I don't see signs of water damage anywhere else.

Thanks, Kyle. Hopefully the new set of spark plugs will be all I need.

sam314159

What do you think about changing out all the ignition coils while I'm at it? I can get all 6 for under $200 so it's not a ton but is it worth it?

Someone suggested that the coils could be going bad too.

sam314159

I just swapped out all spark plugs and coils with new Bosch parts. The car runs like BRAND NEW. No hesitation or codes. All plugs came out pristine except spark plug 3 (the one that was throwing a code). It looks like an oily residue. I cleaned up the well the best I can before I put the new plug in. Any idea what that is?

KyleB

oil probably found its way down into the well at some point. It's on the threads, I wouldn't be concerned.

The electrode portion of that plug looks good, and by good I mean normal wear good. If I saw oil residue on the electrodes I'd be concerned. I think you're in good shape, glad to hear the motor runs well.

cheers.

twh

Could be some oil dripped down there when someone changed the oil and spilled some putting the new oil in. The oil cap on the valve cover has a gasket between the plastic top and the valve cover. Can definitely see that happening.

seven11

its probably a leaking valve cover gasket on the inside

u will need a plug tube also

i had oil in cyl 2, coil had been covered in it, changed the valve cover gasket and spark plug tubes